A conventional example of a linear guide apparatus is shown in FIG. 12. This linear guide apparatus includes a guide rail 100, a slider (also referred to as “bearing”) 200, and a plurality of rollers (rolling elements) 300. The guide rail 100 and the slider 200 are disposed so as to face with each other and have therebetween rolling surfaces 110 and 210, respectively, which constitute a rolling channel for the rollers 300.
The slider 200 can be divided into a slider main body 201, end caps 202 fixed to both ends of the slider main body, and side seals 203 further fixed to both ends of the slider main body in the lengthwise direction of the guide rail 100. The rolling surfaces 210 are formed in the slider main body 201. The side seals 203 disposed at both ends in the linear-motion direction of the slider 102 have respective lips each sealing spaces between the slider 200 and the top face of the guide rail 100 and between the slider and both side faces of the guide rail 100.
The slider 200 also has return channels 221 for the rollers 300 and turn-over channels 222 which cause respective return channels 221 and respective rolling channels to be communicated with each other. The return channels 221 are formed in the slider main body 201 and the turn-over channels 222 are formed in each end cap 202. Female screws 205 which enable attachment of a table, etc., by means of screws are formed in the top face of the slider 200.
Attachment holes for a grease nipple 400 are formed in the side seals 203 and the end caps 202. A lubricant is introduced to an oil path of the end cap 202 through the grease nipple 400, so that the linear guide apparatus is lubricated. The side seals 203 and the end caps 202 are fixed to the slider main body 201 by bolts 500. Attachment holes 120 for enabling attachment of the guide rail 100 to a mounting object like a base by means of bolts are formed in the guide rail 100.
According to this linear guide apparatus, a circulation channel for the rolling elements is formed with the rolling channel, the return channel, and the turn-over channel. The rollers 300 circulate in the circulation channel, thereby allowing one of the guide rail 100 and the slider 200 to take a linear motion with respect to the other.
An example conventional side seal for such a linear guide apparatus has a metal plate and a rubber-made seal member having a base fixed on the metal holder plate. The lip of the seal member is brought into contact with the top face of the guide rail and both side faces thereof when in use.
Patent Document 1 discloses a technology that the holder plate (a casing) of the side seal and the seal member (a seal) with a lip (a sealing lip) are formed of different members, and a scraper which is disposed so as to face the external face of the guide rail with a gap from such an external face is provided at the opposite side of the holder plate for the seal member. The holder plate and the seal are engaged with each other by fitting of a protrusion and a recess. According to such a side seal, relatively large foreign materials are repelled by the scraper at first, and thus the sealing lip can have a longer life and an improved action.
Patent Document 2 discloses a side seal (a scraper) that includes two seal members having respective lips (the sealing lips) inclined in opposite directions to each other, apiece of supporting plate which supports such seal members, and a housing having recesses which receive the bases of such seal members and the supporting plate.
This side seal employs the above-explained structure in order to enable replacement of the seal members without a detachment of the whole slider (a guide carriage) from the guide rail (a guiding rail). Moreover, the supporting plate employs a structure which can support the side seal without deteriorating the function of the side seal in both cases in which the supporting plate supports the two seal members and in which the supporting plate supports only one seal member that is formed of a flexible material.